Many situations exist wherein there is a significant potential for a first moving object to collide with a second object. Such situations are often referred to as conjunctions. An example of a conjunction is a situation wherein a ship traveling on a body of water is at risk of colliding with another nearby ship. Another example of a conjunction is the situation wherein a space asset, such as a satellite, is at risk of colliding with a piece of orbital debris, such as the remains of a damaged rocket.
For the most part, such potential collisions are undesirable. For example, if a ship collides with another ship, personal injuries, loss of life, and/or property damage may occur. If a satellite collides with orbital debris, the satellite may be damaged or destroyed.
If a conjunction is identified, one or more of the potentially colliding objects may are often referred to as maneuvers. A maneuver includes one or more maneuver parameters that define the maneuver. For example, a maneuver's parameters may consist of an epoch, which defines when an object is to execute the maneuver, and a delta velocity vector, which defines how an object's execution of the maneuver will change the object's velocity. As another example, a maneuver's parameters may consist of a start epoch, which defines when an object is to execute the maneuver, a thrust direction, which defines what direction a thruster with specified characteristics is to apply force or thrust to the object, and a burn duration of the thruster.
Unfortunately, an object's execution of a maneuver may create negative side effects. For example, fishing activity or scientific research on a ship may be disrupted if the ship executes a maneuver consisting of changing its velocity. As another example, a satellite's observation activities may be disrupted if the satellite executes a maneuver consisting of changing its path of travel. Furthermore, a satellite may be required to expend energy to execute a maneuver. Such expenditure of energy may be highly undesirable because satellites often have a finite energy source that cannot be replenished. Consequently, if the satellite has to expend significant energy executing one or more maneuvers, its useful lifetime may be decreased.
Negative side effects associated with an object's execution of a maneuver can often be reduced by decreasing the magnitude of one or more of the maneuvers parameters. For example, if a ship or satellite needs to execute a maneuver consisting of changing the ship's or the satellite's velocity, minimizing the delta velocity vector's magnitude may minimize negative side effects. However, a desire to minimize the magnitude of a maneuver's parameters must be balanced against a requirement that the maneuver's parameters have sufficient magnitude to reduce a likelihood of a collision to an acceptable level.
Hence, there is a need for a method of determining a collision avoidance maneuver that is optimized to minimize the magnitude of one or more of its parameters while assuring that the maneuver will accomplish its objectives.